stifle vs unmask

stifle

verb
  • To prevent (something) from being revealed; to conceal, to hide, to suppress. 

  • To prevent (a breath, cough, or cry, or the voice, etc.) from being released from the throat. 

  • To make (something) unable to be heard by blocking it with some medium. 

  • To cause (someone) difficulty in breathing, or a choking or gagging feeling. 

  • To feel smothered; to find it difficult to breathe. 

  • To cause (a dog, horse, or other four-legged mammal) to dislocate or sprain its stifle joint. 

  • To die of suffocation. 

  • To keep in, hold back, or repress (something). 

  • To make (an animal or person) unconscious or cause (an animal or person) death by preventing breathing; to smother, to suffocate. 

  • To treat (a silkworm cocoon) with steam as part of the process of silk production. 

noun
  • An act or state of being stifled. 

  • A bone disease of this region. 

  • The joint between the femur and tibia in the hind leg of various four-legged mammals, especially horses, corresponding to the knee in humans. 

unmask

verb
  • To expose, or reveal the true character of someone. 

  • To cease engaging in masking, to cease disguising one's autism. 

  • To enable (an interrupt, etc.) by unsetting or setting the associated bit. 

  • To remove a mask from someone. 

  • To remove one's mask. 

How often have the words stifle and unmask occurred in a corpus of books? (source: Google Ngram Viewer )